sending your car home for your spouse to use and then back again to pick you up at the end of your day means it's using twice as much fuel on wasted trips with no occupants.
You arent seeing the bigger picture here. If you choose this level of efficiency, after getting dropped off at work, 'your car' will simply locate the next closest customer. If you want to spend the resources on your own private car or a more available one, more power to you.
But people tend to live in the suburbs and work downtown; so the net traffic in one direction is much greater than the net traffic in the other direction.
Well by the time we get driveless cars, we'll probably be on the tenth generation of 'Prius' technology and the wasted fuel cost will be marginal compared to the cost of a car.
Using a 2000 pound block of steel to transport one human being at high rates of speed is fundamentally energy intensive. Even with rainbows and pixie dust it would waste lots of energy.
As the article stated, the automated feature reduces the need for multiple cars, it enables better car pooling options - so yes, if you want to look at it by narrowly isolating one aspect of the scenario, sure, it uses more fuel to drive a car anywhere.
But as a complete solution - which is what the article talks about - the cost of 'wasted' fuel is negligible given the change in behaviours and travel methods that automated cars may bring about.
